PROJECT SUMMARY Source memory involves remembering the context in which a piece of target information (e.g., a fact or statement) was presented. Source memory typically exhibits greater age-related decline than does memory for target information in isolation. Understanding the cognitive mechanisms underlying this decline is thus important to help older adults keep pace with the information age, in which a wealth of information comes from sources of varying quality. A particularly important type of source memory involves memory for the sources of actions. Remembering which people performed which actions is critical to social functioning, allowing one to attribute credit to people who provide help and to assign blame to people who commit negative actions. Kersten et al. (in press) have revealed that the cognitive mechanisms underlying memory for the sources of actions may be different from the mechanisms underlying memory for the sources of verbal information. Source memory for verbal information has typically been associated with frontally- mediated executive functions, such as attentional control, working memory, and set shifting. In contrast, Kersten et al. found that memory for the sources of actions was associated with more basic associative memory mechanisms, likely mediated by medial temporal brain regions. The proposed research is designed to examine the abilities of young and older adults to remember the sources of actions and words, and to relate these abilities to measures of executive and memory functioning. The specific aims of the proposed research are (1) to examine similarities and differences in the cognitive mechanisms underlying young and older adults' memory for the sources of actions and words, (2) to create a set of video stimuli for use by researchers who wish to study memory for the sources of actions, and (3) to collect baseline measures of source memory for actions in a sample of older participants, allowing one to examine the predictiveness of this type of source memory for the later development of pathological conditions associated with medial temporal lobe function, such as Mild Cognitive Impairment and Alzheimer's Disease. The proposed research would achieve these aims by testing healthy young and older adults on their memory for a series of brief video clips depicting actors performing actions or speaking verbal phrases. They will also be given other tests of executive and memory functioning, allowing for an examination of the cognitive mechanisms underlying source memory for actions.